


Closer

by mahbecks



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Demons, Explicit Language, Explicit Sexual Content, F/M, Faustian Bargain, Humor, Light Angst, Romance, Supernatural Elements
Language: English
Status: In-Progress
Published: 2020-10-04
Updated: 2020-11-24
Packaged: 2021-03-08 04:55:55
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 18,156
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26819914
Author URL: https://archiveofourown.org/users/mahbecks/pseuds/mahbecks
Summary: Felix accidentally summons a demon.It turns out both better and worse than he expected.Better, because Byleth is strong and can teach him more than anyone he’s ever met as she helps them win this neverending war.Worse, because in exchange for her help... he sold her his soul.
Relationships: Felix Hugo Fraldarius/My Unit | Byleth
Comments: 37
Kudos: 127





	1. Chapter 1

The problem with humans these days was that no one had any _imagination_.

Byleth was a greater demon - just a few levels lower than the archdevils themselves. Her talents were nigh unmatched, her powers almost limitless. If a human asked her to split the skies open with her blade, she could do it; if they asked her to rend the very earth beneath their feet, she would. She could break the world and make it whole again in the blink of an eye - make it even better than before. 

Instead, they sold her their souls for money, sex, and a lifetime supply of whatever cheap thrill of the moment was most popular. 

There was no ambition, no drive - instant gratification, that was all humans wanted these days.

Personally, she blamed Rhea. The archdevil had started some church a few hundred years ago, some cult in her own image. To stabilize the human realms, she’d said, and promote a sense of peace of order. It encouraged moderation and virtue, chastising excess - which of course meant that its adherents craved nothing more than abject hedonism, in the few moments they were honest with themselves. 

Byleth had always found that a bit cruel - telling humans that the “goddess” would grant them peace, prosperity, and their greatest desires, if they just obeyed the church’s teachings and adhered to her tenets, all while knowing that it was a huge crock of bullshit.

But then, Rhea always had been a bit of a bitch. 

She wasn’t sure why Sothis didn’t put a stop to it - she’d mentioned to Byleth several times that she thought Rhea’s church was stupid, a level of vanity even a devil should be ashamed to dispay.

It wasn’t if Sothis didn’t have the authority to end Rhea’s machinations - as the queen of hell, her word was law. Their power as demons and devils, though very great, was nothing compared to hers. 

So far, though, Sothis hadn’t seen fit to do anything about Rhea’s little pet project. She slept, waking long enough to accept the souls they offered her at the end of each tithe, before slumbering once more, leaving them to their own devices.

Byleth would find no ally in her queen. And so she went on, day after day, granting human wishes for heaps of gold and jewels, beautiful, luscious lovers waiting for them in their bedrooms, and pleasure beyond their wildest dreams in exchange for the only thing they possessed of true value.

Their souls.

Ten years of whatever they wanted, and their soul was hers. It wasn’t a fair bargain, really; humans didn’t seem to know the value of what they possessed. They could easily have argued for a hundred years, and it would have been a much fairer price.

But that brought her to the second problem with humans in this day and age - they didn’t _haggle._

No one ever asked her for a better deal. No one rebutted with a counteroffer. They were so eager, so _ready_ for what she promised them. She was willing to wager more than half of them didn’t even read the contract she provided before they signed.

A travesty, truly.

But that was what made her current quarry so intriguing.

He didn’t want fame or glory - no. In fact, she rather got the impression that he couldn’t care less about such things. And he couldn’t have been after wealth. His clothing, his weapon, his general hale and healthy state of being: all things suggested that this was a man who’d never had to worry about having enough coin to make his way in the world. And where there was money, other things often followed. 

So what, then, did he want?

She supposed she could be making an assumption here - the other humans with him could be the one to offer up their soul on her altar. It wasn’t necessarily the dark-haired one. 

Perhaps it was the redhead, sitting tall and proud on his destrier, who would ask her for his heart’s desire. Maybe the lone woman would ask her a boon. Or maybe it was the hulking blonde in the back who would demand a gift - their leader, if she had to hazard a guess.

Any one of them would do. Souls weren’t necessarily equal in value - as Hanneman had often lectured her, a human’s individual strengths of character affected the quality of a soul, yes, its overall capacity to sustain demon life. But they _were_ all valuable, and so she found she generally wasn’t picky when it came to selecting victims.

...subjects?

...business partners?

She’d never known what exactly to call the humans who sold her their souls. 

Still.

Today, she found herself hoping it was the dark-haired one. 

She couldn’t say why - there was just… something magnetic about him. The fluid way he moved, how his sharp eyes darted around their surroundings, each flick of his gaze like a caress he didn’t know he was giving - this man was dangerous. 

This man was different.

Byleth darted her tongue out, wetting her suddenly dry lips, and settled back to wait and see what the humans would do next. 

* * *

“What exactly are we looking for again?” 

Ingrid sighed, pulling up on the reins of her horse - a borrowed mount from the stables, as her pegasus would do them no good in the middle of a forest. “An altar,” she replied. “A demonic altar, in the middle of the woods.” She sighed. “This is a-”

“A bad idea,” Felix snapped. “We know.”

“You… have mentioned it, Ingrid,” Dimitri added. “Several times.”

“And I’ll say it again,” she snapped. “This is _stupid.”_

Privately, Felix agreed. 

He’d never been very superstitious - the legends and tales of ancient demons who would grant you your deepest desire in exchange for your soul were just that. Tales. He’d never heard of anyone ever _actually_ stumbling across a demonic altar or being offered a deal. People had scoured the land for years - scholars, cynics, the desperate. None of them had come back with anything to show for it. 

So the fact that the four of them were even out here, traipsing about in the wilds of northern Faerghus, searching for some altar that more likely than not didn’t even exist… stupid.

Monumentally stupid.

But then, they _were_ desperate, and desperate people often did stupid things.

It had all started, predicatibly, with Sylvain getting drunk in a tavern.

The excessive drinking, Felix had begrudgingly accepted; they’d lost yet another battle, having to cede even more ground to the Adrestian Empress in her reckless war to unite all of Fodlan. It had been a rout, the Faerghan forces having to flee to avoid total ruin, and what remained of their southern army was almost totally demoralized. He would have been drinking too, if he liked the taste of cheap beer.

But he didn’t, and so he’d sat in a corner, arms crossed over his chest, getting angrier and angrier as Sylvain had gotten drunker and drunker. 

Sylvain was a friendly drunk - the kind of person who could and would befriend anyone else in the vicinity. At first, he’d cozied up to the bard strumming a lyre in the corner, begging her to sing him a song. She’d placated him for a while; but eventually, she’d gone off to bed, her purse much fatter than it had been several hours ago, and Sylvain had had to find someone else to bother.

He’d settled on a long-faced young man sitting at the bar, dressed in a set of colorful robes that were decidedly not appropriate for a northern winter. 

The two of them had really hit it off, spending several hours discussing the young man’s research - demonology, as it turned out. He was interested in the legends of demonic altars and the deals humans could make there, whether or not there was any truth to them. The Empire, he insisted, didn’t allow such investigations - Edelgard had made certain of that, banning both the church and the study of anything even remotely supernatural soon after she’d ascended the throne.

Rather than see himself be branded a heretic, Linhardt von Hevring had packed up and traveled north.

Somehow, he’d deduced there was one such altar in the surrounding forest. He’d said something about triangulating the origins of several of the most popular of the tales, pinpointing this area as the epicenter. Felix hadn’t really understood most of what he was saying; for one thing, Linhardt couldn’t talk without falling into hopelessly arcane jargon, and two, he really _couldn’t_ have cared less about what the man had to say. 

They should focus on what they could actually do, he’d argued, not go chasing ghost tales. 

But then Linhardt had suggested that maybe such a deal with a demon could help them win this war, and Dimitri had been sold. 

Single-minded to a fault, he wouldn’t rest until he’d defeated Edelgard and all of Adrestia. The war had consumed him, utterly, for the past five years - ever since his father had died at the Tragedy of Duscur and the Empire had been proved to be to blame. He would claim that he was doing this to protect Faerghus, to maintain the kingdom’s integrity. And in recent years, he’d gotten a better hold on the fervent desire for vengeance that had taken ahold of him upon Edelgard’s crowning. He wanted revenge, yes, but now he claimed he was more interested in restoring the _peace._

Felix still wasn’t sure he bought it. 

He’d been there, that day when they’d learned of the old Emperor’s abdication. He’d been there when it had come to light that Adrestia had been responsible for the Tragedy. He’d seen the cloud of rage that had passed over Dimitri.

It was hard to reconcile _that_ boar with the man Dimitri had become. 

He supposed it didn’t really matter anymore whether Dimitri was fighting this war for peace or revenge. They both required the same thing-

Edelgard’s head on a spike, her armies destroyed, her castles torn down. 

And so here they were - knee deep in the muck, cold, chasing a fucking _story._

“Do you see anything?” Dimitri raised a hand, peering off into the distance. “A temple, or some such?”

“I thought we were looking for an altar,” Ingrid said.

“Well, yeah, but an altar isn’t gonna be out in the open on its own,” Sylvain replied. “It’ll be, like - part of a complex or something.”

Felix scowled. “How the fuck would you know?” he demanded. 

“Well, Linhardt said-”

“Linhardt said a lot of things.” Felix huffed, shifting his shield into a slightly more comfortable position on his back. “And where is he? Why isn’t he here?”

“Ah, that,” Sylvain laughed, running a hand through his hair. “He didn’t really, you know, have the right shoes for this sort of trek-”

“...the right shoes.”

“- _and_ I couldn’t wake him up this morning.”

Ingrid pinched the bridge of her nose. “So our one source of information is back at the inn we just left, fast asleep.”

“...yeah, pretty much.”

“Great.”

Dimitri, ever their stoic leader, stepped forward, laying a hand on Ingrid’s arm. “Take heart, Ingrid,” he said, offering a smile that didn’t quite reach his eye. “The day is young! We may find the altar on our own.”

She offered him a weak smile in return, and Felix rolled his eyes. 

Idiots. 

Hopeless idiots, the both of them.

...he wasn’t sure what that said about him, following them on this fool’s errand. 

Nothing good, probably. 

They pressed on, spending the better part of the morning going deeper and deeper into the forest. The trees were thick here, long, twisting branches keeping out most of the sunlight even though their leaves had long since fallen. Combined with how the path narrowed, forcing them to dismount from their horses and move in one straight line, and it was downright oppressive, ominous. It made Felix uneasy. 

But it wasn’t just the forest that had him on edge - 

Someone was watching them. Studying them. Like a predator watches prey.

He could sense it, even if he couldn’t see them. More than once, he caught himself looking back over his shoulder, trying to pinpoint the watcher’s presence. 

He didn’t see a damn thing.

It made him angry, and he found his hand drifting down to rest on the pommel of his sword. 

He nearly jumped when Dimitri leaned in over his shoulder and murmured, “I sense it too.”

“Fuck off,” Felix snapped, taking a few steps forward. 

Dimitri ignored him, his one good eye flicking from left to right. “There’s something out there.”

“Don’t say that,” Sylvain said, swallowing. 

“An animal?” Ingrid guessed, reaching for her own weapon. 

“I don’t think so,” Dimitri replied. “Animals don’t stalk humans.”

“Is that what’s happening here?” Sylvain asked. “We’re being stalked?” His voice rose a little on the last bit, and he twisted his stallion’s reins nervously in his hands. 

Felix huffed out a breath, taking the lead and pressing on through the woods. 

“If you’re afraid, go back to the inn,” he sneered. 

“I’m not afraid!” Sylvain protested. “I just - I just have a healthy respect for things that may or not be hunting us. That’s all.”

Felix snorted. 

Despite Dimitri’s assertion to Ingrid, he thought it more likely their observer was some kind of animal - a big one, maybe, one that wasn’t afraid of humans. Or one hungry and desperate enough to attack a group like theirs. Maybe even a pack of them. But if he was right, and it was a person, and they _were_ being followed-

Felix’s grip tightened on his sword. 

Well.

He was prepared for that. 

The prickly feeling between his shoulder blades only intensified as they continued on, but nothing ever came of it. Though he kept vigilant, eyes flicking between the trees at his left and the trees at his right, he didn't see a damn thing to indicate the presence of anything else - no flash of teeth, no gleaming eyes. No snatch of fabric or glint of metal.

He didn’t like this.

He preferred his enemies out to the front, where he could see them. Not lingering in the shadows, always a step out of his reach.

Perhaps an hour later, all of them on edge now, Ingrid came to a halt, raising a hand to her brow. 

“Is that-”

Felix followed the line of her gaze; sure enough, several hundred feet away was a break in the trees, a clearing just beyond that. Sunlight, bright against the dimness of the woods, filtered down through the branches, alighting upon what appeared to be-

“You’ve got to be shitting me,” Felix snapped.

“Huh. An altar, but no temple,” Sylvain mused.

“No, no, there are columns,” Dimitri pointed out, waving a hand towards the right. “Broken, like ruins, but I can see the plinths. The roof must have been destroyed.”

“Oh yeah, I see them now.” Sylvain leaned forward for a better look. “What do you think tore down the temple?”

“Time,” Dimitri replied. “As will come for us all.”

Felix barely suppressed a gag, pushing past the others and into the clearing. An altar did indeed stand in the middle - if it could be called that. Realistically, it was just a slab of stone supported by several other flat stones. There was nothing else to distinguish it as some sort of ceremonial object - no inscriptions, no glyphs, no runes.

And certainly no bones or bloodstains.

He was almost disappointed.

“What do we do now?” Ingrid stepped up beside him, looking down at the altar with a distasteful look on her face.

“Is there some sort of offering we must make?” Dimitri mused, running a hand along the stone. “Gold? Blood?” He reached a hand for the hunting dagger at his waist. 

“Wait, wait, wait.” Sylvain popped up on the other side of the altar, back on his own two feet. “Hold up a minute. Are we really doing this?”

“Doing what, Sylvain?”

“Trading our souls for something to help us win the war.”

Felix snorted. “Like that’s really going to happen,” he scoffed. 

“But if it _does-”_

“If it does, it’ll be sheer fucking luck.”

“I can’t believe I’m saying this, but Sylvain is right,” Ingrid interjected. “We should at least have a plan.”

Dimitri nodded. “Agreed.” He looked to each of them in turn, then, his expression becoming quite serious. “I do not ask any of you to make this sacrifice yourself. I will trade my soul to the demon for-” He paused, thinking.

“For…?” Sylvain prompted. 

Dimitri put a hand to his chin. “I… I don’t know. What should we ask the demon for?” He paused, frown deepening. “What will help us win this war?” 

“Gold?” Ingrid suggested.

“More soldiers?”

“A weapon.”

Ingrid frowned at Felix. “But Dimitri already has Areadbhar. And I have Luin, and Sylvain the-”

“And Edelgard has Aymr, and Gloucester has their own relic - that’s my point,” Felix explained. “We have relics, and so do they. They cancel each other out. We need something better. Something _stronger.”_

“Felix, that’s-”

“No,” Dimitri said, making Ingrid pause. “I think Felix is onto something.”

Felix liked being right - everyone did. But he disliked the way agreement sounded in Dimitri’s mouth. 

“We aren’t lacking for men, thanks to Margrave Gautier’s recently finalized treaty with Sreng,” Dimitri continued. “And once Sylvain marries the Srengi princess, her dowry will provide enough gold to pay our armies and keep them fed, clothed, and armed for the foreseeable future.”

“Yay, me,” Sylvain said weakly. 

“So what we need is a weapon, something powerful enough to stop the Empire in its tracks.”

“But what sort of weapon is that?” Ingrid wondered. “It can’t be just any old sword.”

They all paused to consider this. 

A weapon.

A weapon strong enough to turn the tide of this war. 

What form could it possibly take?

“A beast of some kind?” Ingrid mused. “To counter Edelgard’s crest beasts?” 

“A giant… battering ram?” That earned Sylvain dark looks from both Ingrid and Felix, and he threw his hands up defensively. “What? She’s got a lot of heavily fortified defensive positions! We’re gonna need a ram eventually!”

“We aren’t going to waste a deal with a demon on a fucking piece of wood,” Felix spat. 

“Ah, but I thought this wasn’t even going to _work,_ right, Felix? So why do you care if we waste the deal or not?”

“I was being hypothetical,” Felix snapped. 

Sylvain smirked at him. “Uh-huh.”

“Maybe it isn’t about the weapon so much as the one who wields it.” Dimitri’s voice cut their argument short. “Maybe… yes, that… that might work.” He looked up, as if he’d just now remembered the rest of them were there. “We must ask the demon for a warrior strong enough to turn the tide in our favor.”

Felix wasn’t sure any one person was enough to do that. He said as much, but Dimitri just smiled at him and put a hand on his shoulder.

“Have faith, Felix - this will work.”

Felix shrugged off his hand, barely containing a snarl.

Dimitri seemed not to notice, his gaze going distant once more. “It must work,” he murmured. 

Sylvain laughed nervously into the silence that followed, looking from Felix to Dimitri. “So, how do we do this thing? Now that we know what we want, and who’s going to ask. How do we start?”

“You didn’t discuss that with Linhardt?” Felix demanded.

“He, uh, neglected to mention the exact steps-”

“There must be some clue… some sort of instruction,” Dimitri said, walking around the altar. “Surely whoever made this wouldn’t have created it without guidance.” He bent down, inspecting the underside of the main stone. “Ah! Here it is.”

They all crowded around the spot Dimitri had pointed to, nearly knocking their heads together in the process. Sure enough, there was a line of rudimentary drawings scrawled across the underside of the rock. They were crude, roughly hewn into the altar - and no doubt very, very old. 

“What does it mean?”

“They look like symbols of some kind - an old language maybe?”

“No,” Sylvain said. “I don’t think so.” He pointed to one. “I think… I think they may actually be _crests_.”

“What?”

“Yeah, look - there’s Gautier there,” he said excitedly, pointing to a symbol near the end of the line. “And there,” he added, his finger moving along to rest on another drawing, “That’s Fraldarius there!”

“Then… we use the altar by using our crests?” Ingrid guessed. 

“Or our relics,” Dimitri offered. “But yes - I would think that would summon the demon.”

Felix stood, not liking this one bit. 

They hadn’t brought their relics - Sylvain, Dimitri, Ingrid. Lances all, they were too unwieldy in the close quarters of a forest; in a fight, they’d just end up caught in the branches and brambles. They’d traded their relics for swords, leaving their true weapons safely guarded back at the main camp. 

But the Fraldarius relic wasn’t a lance - it was a shield. 

The shield currently strapped to Felix’s back. 

It fucking figured. 

All eyes turned to him as he unstrapped the Aegis shield - Ingrid and Sylvain’s worried, Dimitri’s hopeful. So fucking hopeful, as if he’d just found salvation, if only Felix would give it to him.

Felix hated it.

“Don’t look at me like that,” he snapped, holding out the shield. 

“Felix-”

He ignored Ingrid, looking only at Dimitri. “Just - just fucking take it. Take it, make the deal, and win the damn war.”

If it worked.

If it was true.

He still wasn’t convinced any of this was real. But to hell with it - what did it hurt to try? If it worked, maybe they’d actually stand a chance against the Empire. If it didn’t, well - they were no worse off than they had been yesterday. 

...right?

Dimitri took the shield, thankfully saying nothing, and turned to set it on the altar. He laid it down gingerly, its gleaming outward edge facing up, and then took a step back, expectant.

Nothing happened.

One second turned into ten, which turned into a minute. Still, no demon appeared. 

“Did it… did it work?”

Felix turned to scowl at Sylvain. “What do you fucking think?”

As if to spite him, the breeze picked up, sudden and cold, whipping at their cloaks and hair. There hadn’t been a bit of wind all day; for it to be picking up just now seemed… awfully coincidental. Felix’s hand found its way back to his sword, drawing it in one fluid motion.

“I don’t like this.” Ingrid shifted uneasily on her feet. 

The feeling that someone was watching them intensified tenfold, and he spun on his heel, slipping into a defensive stance. 

“Show yourself!”

There was someone there, just beyond his sight, he _knew_ it. If he could just _see_ them-

Behind him, he could hear the rest of them drawing weapons. Ingrid rushed to take point beside him, her hands steady on her sword despite the open fear on her face. 

“Where are they?” Sylvain asked, turning to guard Felix’s flank. “Do you see them?”

“There!”

Felix turned to see what Dimitri had found, only to find the other had already rushed forward to a spot in the distance, something having drawn his gaze.

”Hey, wait-” Sylvain called out, taking a few steps forward. “Dimitri!”

He never made it to his destination; halfway across the clearing, something long and metallic - a whip? a chain? Felix couldn’t even see it for its speed - snaked out and hit him hard across the chest, throwing him backwards into a tree. Something cracked ominously as he made contact, and when he fell, he didn’t get back up.

“Shit,” Sylvain breathed. 

“Your Highness!” Ingrid screamed.

They were next. Sylvain managed to parry the first attack before he too went down, axe knocked from his hands. Again, Felix didn’t even get a chance to see the weapon before Ingrid too was down for the count, a bruise forming on her temple.

His grip tightened on his sword, and he turned his gaze back to the front, bracing for the attack. 

It never came, even after several long minutes.

Somehow, that was worse.

Just as he’d made up his mind to lunge forward and go on the offensive, a woman stepped out of the forest, coming to a stop on the other side of the altar. Felix had never seen her like - her hair shone bright green in the sunlight, framing a wide-eyed, blank face, tumbling down over an outfit comprised of nothing but leather and black lace. A sword in her hand, its blade strangely segmented, she was undoubtedly the source of the unexpected attacks. But she was holding it down at her side, her posture relaxed - like she meant him no harm. Felix didn’t buy it; this was a trick, a ruse to draw him into attacking so she could cut him down. He was sure of it.

He widened his stance, sword held out before him.

“Who are you?” Felix demanded. 

The woman blinked, her green eyes eerie, lambent, but said nothing.

He scowled at her silence. “I won’t ask you again!”

Her eyes flicked down to the altar, eyeing the Aegis shield still lying on its surface. She blinked once, twice - and then reached out a hand, trailing her fingertips down the metal. 

“Hey! I’m talking to you!”

She looked up again - and though her expression hadn’t changed, not really, if he wasn’t mistaken, there was something like _amusement_ in her eyes. 

“It _was_ you,” she said. 

Felix shifted, not daring to look away even as one of his friends groaned behind him. 

“I didn’t think you’d actually do it. But this is yours.” The woman sighed, setting her sword aside and gracefully settling down onto the altar. “You summoned me.”

She _was_ the demon then. Fucking obvious, in hindsight. But then her words caught up with him, and he shook his head violently. 

“I did _not-“_

Her head tilted to the side. “Then this isn’t yours?” she asked, tapping a finger on the shield. 

He bit back his hot retort, and one corner of her mouth curled up into a smirk. Still watching him, she patted the altar beside her, beckoning him over.

“Have a seat, Felix. Let’s talk.”

**Notes for the Chapter:**

> This little plotline was borne out of a very long car ride and hasn’t left me alone since. I wanted to do some something kind of spoopy for October anyway (if this even counts as spoopy lol horror isn’t my forte, so we’re going the humor-supernatural route) so I decided to give it a go!
> 
> Thanks for reading, as always! :) And Happy Halloween


	2. Chapter 2

Felix didn’t lower his sword, and he didn’t stand down.

Byleth wasn’t surprised. 

But she was immortal; she didn’t have anywhere to go, or anything else to do. She could afford to be a little patient. So she sat there, one leg crossed over the other, taking the time to study her quarry as she waited. 

Up close, his face was even more elegant than it had appeared at first glance. Sharp cheekbones sat below a pair of even sharper eyes; his angular chin jutted forward rebelliously as he grit his teeth at her, doing nothing to hide the surprisingly full set of his lips. It was an almost delicate face, pretty. 

She decided she liked the look of it.

“What are you staring at?” he demanded, those molten eyes narrowing. 

“You,” Byleth replied.

Her bluntness seemed to unnerve him, and he huffed out a breath. “Stop it.”

“Why?”

“I don’t like it. You look at me like-” He snapped his mouth shut, biting off whatever he’d been about to say. 

“Like what?” she prompted.

He hesitated, mouth pulling taut. For a long moment, he fought with himself, debating whether or not to answer. 

“Like I’m something to eat,” he said finally. 

Byleth blinked.

“Well, I am a demon.”

She was messing with him - mostly. Demons didn’t require food the way that humans did. Instead, they consumed souls for sustenance - the process was similar to the way a plant absorbed nutrients through the soil, though a few curious individuals had managed to figure out a way to consume them like a human would a strong drink. 

Manuela was nothing if not resourceful. 

And even if demons _had_ needed food, she wasn’t sure she would resort to human flesh. Years of following humans around - and catering to their more carnal desires - had shown her a world of venereal diseases and parasites that she’d liked to have remained delightfully ignorant about. 

Not to mention the way that some of them _smelled_?

No, thank you.

He scowled. “Disgusting.”

“I don’t plan to eat you, Felix,” she replied, once again patting the stone beside her. “I just want to talk to you.”

He didn’t look as if he believed her. 

Byleth changed tack. “Why did you summon me, then, if you have no intention of speaking with me?” she asked. 

“I _didn’t,_ ” he spat.

She sighed. “I thought we were past this, Felix-”

“ _He_ summoned you,” Felix retorted, jerking his head towards the blonde man who’d first attacked her - Dimitri, if she recalled correctly. “Not me.”

“He put the shield on the altar, but it’s your crest that summoned me,” she explained. “That’s how they work - the altars. This one, at least.”

They weren’t all this specific; some were attuned to crests, yes, but others required less to activate. A handful of coins, a large gemstone. Furs or precious metals. A few even accepted blood, though a fellow greater demon by the name of Seteth had made an appeal a century or so ago to have those particular altars shut down. 

It gave demonkind a bad _image,_ he’d said. 

She wasn’t sure whether the appeal had passed or gotten lost somewhere in the annals of pandemonic bureaucracy, but she distinctly remembered the attempt. 

Personally, she would’ve just - you know. Smashed the damn things to bits. But that wasn’t Seteth’s style. 

“I don’t want anything to do with you,” Felix announced. 

Clearly.

She began to suspect that she might have miscalculated how easy this would be; getting Felix to work with her was going to require a little more effort on her part. 

It was time to force his hand. 

She stood, one hand grabbing for the shield and tossing it to the ground. 

“Fine.” She nodded towards his companions, still sprawled out behind him. “Take your friends and go. Come back once you’ve got another relic.” Then she turned on her heels as if to leave, shrugging him off like a cloak. 

“Wait.”

Her lips curved up into the smallest of smirks, and she paused, looking back over her shoulder, victorious. “Yes, Felix?”

“Don’t go yet,” he said. 

She turned more fully, facing him once again. 

Slowly, as if it pained him to do it, he lowered his sword, falling out of his battle stance. 

“I need your help.”

There. Was that so hard for him to admit?

...judging from how hard his jaw was clenched, yes. Yes, it was.

“We’re at war,” he continued. “We have been for five years - and we’re losing. Badly.” 

Byleth knew that - not because she kept up with human affairs, but because it was just impossible to avoid. She couldn’t go anywhere in Fodlan these days without hearing of its effects; every tavern, every brothel, every street vendor and every church… at each and every one, there’d been talk of this war. Some were exuberant, gleeful at the Empire’s success. Others were more somber, having lost loved ones along the way. But one universal truth was that there was no one who remained untouched - including demonkind.

War, as it turned out, was good for business.

Their services were in high demand, everyone clamoring for a deal of some kind. What was death in ten years, they argued, when they didn’t know if they were going to last the next month? Better to die happy, having gotten at least a taste of your deepest, darkest desire than alone and miserable, with no such succor.

“We need - we need help.”

“Help.”

Felix scowled at her. “Yes, help.”

She leaned against one of the nearby rocks, crossing her arms over her chest. “You’ll have to be more specific than that.”

It was a technicality - an annoying one, in her opinion. 

She’d overheard their conversation; she knew what Felix and his companions needed. But the human who made a deal with a demon had to voice their desire aloud - she wasn’t allowed to make assumptions. 

“We need -” He hesitated; it was clear this was difficult for him to admit. “We need someone to help us defeat the Empire’s armies. Someone strong.”

She tilted her head to the side in question. “Are you asking for skill?” She eyed him, gaze traveling over his trim physique, recalling the ease with which he’d handled his blade. She was willing to bet he was plenty skilled already.

He flushed at her scrutiny. 

“I’m asking for _help_. A warrior. Someone to lead our armies.”

“A champion.”

“...yes.”

“Why not him?” She pointed a finger at Dimitri. “He seems the type.”

“No,” Felix said quickly, free hand clenching into a fist. “Not him. He’s too-” He snapped his mouth shut again, once more cutting off whatever he’d been about to say. “He’s not good enough.”

“What about you?”

He looked down at his feet. “I’m not good enough, either,” he muttered. 

“Do you want to be?” 

His eyes flashed. “No one can win this war on their own,” he snapped. “No one’s that strong.” 

“Probably not,” she agreed.

“But you-”

_Ah-hah._

Now she saw where he was going with this. Dimitri had spoken of a champion for their cause, someone to turn the tides. No doubt he’d meant some soldier, a paragon to come out of the woodwork and lead them to victory. 

Felix had a different sort of leader in mind.

“You could make a difference.”

She nodded once, curt. “Yes.”

“And that sword-”

“This?” Byleth bent down, picking up her weapon and holding it out before her. Felix eyed it reverently, taking a half step forward before remembering who - and what - she was. 

“Is it a relic?” he asked. 

“The Sword of the Creator,” she replied. “Gifted to me by the queen of hell herself.” She returned to his question, thinking it over. “Demons don’t really have relics - not like humans do, at least. But I suppose it is similar.” To demonstrate, she pulled her collar to the side, exposing the brand that had been carved into the skin of her neck for as long as she could remember. “Only those who bear the queen’s mark can use this sword.” 

His eyes lingered on the brand longer than was strictly necessary before flicking back up to her face. 

“It’s strong.”

“Yes.”

“And with it, you could fight with us.”

It wasn’t a question of whether or not she _could,_ but rather if she would. This would require much more time and effort than she normally spent to harvest a soul. With most humans, the deal was made, she granted the desire, and then went on her way, returning in ten years to collect. When the human was particularly interesting, she made it a point to check in more frequently - once a year, perhaps.

What Felix was asking would require her constant attention for the next decade. She wouldn’t be able to leave, at least not until the war was finished. And while she was busy fighting battles, she wouldn’t be able to make any more bargains. Her next tithe would be small - dangerous ground for a demon. 

They had quotas to meet, the same as anyone.

But the soul of Felix Fraldarius - son of a noble house, the bearer of a _major_ _crest_. That wasn’t just any soul. If she brought it to Sothis, offered it up like the prize it was…

Oh, she could just _taste_ the envy on Rhea’s face. 

Her decision made, she returned her attention to Felix, nodding. 

“I could.”

“You’d make a difference.”

She shrugged. “Probably.”

_Definitely._

He took another step toward her, more confident now, less wary of her. 

Time to drop the news, then.

“For a price,” she reminded him.

He halted, tensing.

“You must know nothing from a demon is free.” 

His eyes flicked from her to Dimitri, still out cold on the other side of the clearing. 

She shook her head. “That won’t work.”

“What?”

“Like I said - _you_ summoned me, Felix. Not him.” She straightened, finally sheathing her sword at her waist. “You want my help? Then _you_ have to make the deal.”

He didn’t like that. 

“We can come back,” he argued. “He’ll bring his own relic and summon you.” 

“You can,” she agreed, “but there’s no guarantee I’ll still be here.” 

His brow furrowed. “Where else would you go?” 

Byleth raised her eyebrows. “Anywhere I damn well please.” 

“You’d just… leave?” He scowled. “But we need your help!”

“So do countless other humans,” she pointed out. 

He sneered. “People wanting sex and drugs, is that what you mean? They need help, but not yours.”

She lifted an eyebrow. 

“We _need_ your help,” he pressed. “People are depending on us - on us leading them to victory and winning this damn war!” 

“So what you want is more important than what other people want?”

“I - that isn’t what I said,” he said.

“It sounds like it.”

“ _This war_ is more important than what any one person wants, because if we don’t win, _no one_ gets what they want! Too many will die, and Edelgard will burn the countryside to the ground. I’m trying-” He huffed, struggling for words, tugging at his hair with his free hand. “I just want to-” Again, he faltered.

She got it.

Or, she thought she did. 

She didn’t really understand most human motives and desires. But she did know what it was like to want to protect someone. 

Felix wanted to protect someone - his friends, maybe, or family. Perhaps a lover. Or maybe it was more complicated than that, and he didn’t even know what exactly he was trying to protect. 

“What’s the cost,” he finally bit out. 

She blinked. “Your soul.”

“That’s it?” 

Well...

Yeah. She supposed that _was_ it.

“Do you know what that means?” she asked, frowning. 

“I die.”

“...that’s part of it, yes.”

He snorted. “What else is there?”

“It’s your _soul,_ Felix. Without a soul, you-” She frowned. “You should know all this. Isn’t it in the legends somewhere? Do none of you read anymore?” 

“I read,” Felix snapped. 

“You’re asking an awful lot of questions for someone who knows how this works-”

“What, you mean I go to hell?” he sneered. He threw his arms wide. “Look at Fodlan. I’ve _been_ in hell the past five years, demon.” 

“You say that _now-_ ”

“Well, then you’ll have all of eternity to tell me you told me so.” He huffed out a breath, shifting from one foot to the other. “So what do I get out of this?”

“My help in winning this war,” she said slowly. “As we just discussed.”

He scowled. “I _know_ that. What else?”

Byleth was taken aback at first, too used to humans latching onto their first desire to think that they might have a second. But then she smiled, because Felix was thinking on his feet, feeling out his options as he went along. 

Another thing about him that she liked.

“What else did you have in mind?”

“Teach me.” 

“...what?”

No one had ever asked her to teach them before. Grant them the skills they needed for fame and fortune? Sure. She’d done that a couple of times. But Felix wasn’t asking for skills; he wanted to _learn._ He wanted to earn his abilities the old-fashioned way. 

“Teach me,” he repeated. 

“You’re a soldier,” she pointed out. “You know how to fight.” 

He snorted, looking around at his fallen companions. “You took them out before I could even move,” he said. 

She lifted an eyebrow. 

“Again - I’m a demon.”

“So?”

“So that was hardly a fair fight. I’m faster than any human ever will be - ever _could_ be.”

“Exactly.” He pointed a finger at her, determined. “You’re better than any sparring partner I’d find back at camp. If anyone can show me more than I already know, it’s you.”

He had her there. 

It was an intriguing prospect - a protege. A student. She’d done some rudimentary sparring with Seteth’s daughter, Flayn, but the girl wasn’t a fighter. A lesser demon, she dealt more with soul maintenance than collection. It meant she didn’t often go out into the field. She’d not warmed to the training in the way Byleth had hoped. But Felix…

 _He_ was a warrior - she saw it in the way he held his sword, in the way he held his body as he moved. She could push him, and he would push right back. He’d take everything she could give him - and then some, demanding the very best. 

He would be a challenge, the first she’d had in - well, a very long time, if she was being honest.

“Alright,” she said, nodding. “I’ll teach you.”

His eyes widened, as if he hadn’t thought she’d agreed - but then he nodded, satisfied. 

“Anything else?” she asked. “A sword to go along with your lessons?”

He scowled. “I already have a weapon.”

She raised her eyebrows. “You mean you don’t want something big and heavy and covered in enough gemstones to feed a small village-”

“No.”

“Are you taking requests? I’ve got something,” a bleary voice announced. 

Startled, Felix whirled around just in time to see the redhead push himself out of a puddle of mud and up onto his elbows, a lazy grin on his face. 

“Ask the pretty lady for a kiss, Felix - she’s just your type. I’d ask her myself but I’m-”

He didn’t get to finish the sentence, Felix rushing forward and going to one knee as he looked his friend over for injury. Byleth was confident he wouldn’t find any - she hadn’t hit the man _that_ hard. 

And judging from the way he was ogling her breasts, he wasn’t having _any_ difficulty keeping focus. 

“You idiot,” Felix snapped, slapping away the feeble thumbs up gesture Sylvain was making. “Now’s not the time for that.”

“What? It’s always the right time for true love.”

Felix snorted. “She’s a demon,” he hissed. 

Sylvain looked back at Byleth, offering her a wink. “That’s hot.”

“They’re incapable of love.”

Now it was Sylvain’s turn to laugh. “So are you,” he retorted, “You heartless bastard.” He reached a hand out for Felix to help him up. 

Felix shoved him back in the mud. 

Byleth fought to hide a smile behind her hand. 

“I don’t want a kiss,” Felix said stiffly, cheeks flushing red. “Not from you.”

“I’m crushed,” Byleth replied. 

“And I don’t want a stupid sword that doesn’t work. The one I have works just fine.”

“Fine.”

“Fine.”

“Get a room,” Sylvain muttered. 

Felix ignored him. “How do we do this?” 

“How do you sign your life away?” 

Byleth snapped her fingers, a contract and charcoal pencil conjuring out of thin air and floating down to the altar. It was a bit much, personally - another of Manuela’s inventions, much too showy for her tastes. But the spell _was_ a hell of a lot more convenient than carrying around a bag of stationery. 

She bent down, scrawling her signature across the first line at the bottom of the last page and then turning to hold the pencil out to him.

“Like that.”

“...that’s a little on the nose, isn’t it?”

“Tell that to the record keepers in the Archives. There’s a document for everything.”

“There’s paperwork in hell?” 

“Hell is nothing _but_ paperwork.” 

He snorted at that, taking the charcoal from her and stepping forward. He bent over, right hand poised over the pages, ready to sign-

“Felix!” Sylvain grabbed him by the shoulder, yanking his hand away. 

Byleth scowled. They’d been so _close-_

“You can’t just sign something without reading it!” 

Felix shrugged him off. “I don’t _want_ to read it-”

“I know you let Rodrigue handle most of your paperwork, but Goddess, Felix - here, let me look it over.” 

Before Felix could protest, he pulled the contract away, looking it over with a calculating eye. 

“Like you understand any of that-”

“I do, actually. It’s a fairly standard legal document.” 

Felix turned to Byleth, who shrugged. “Our main clients are career politicians and magistrates,” she replied. “No sense in wasting their talents once we collect.”

He scoffed, turning back to Sylvain. “Are you finished?”

“Almost.” Sylvain flipped to the last page, scanning over the contents. “Gimme one… sec… okay, finished. Yeah, it checks out - no nasty surprises embedded in a secondary clause, no fine print.” He looked at Byleth. “I’m surprised - I’d’ve expected more tricks from a demon.”

“No need. Anything we wanted we could take.”

Sylvain winced. “Point taken.” 

“Are we done here?” Felix demanded. “Can I do the damn thing we set out to do?”

Sylvain didn’t relinquish the contract, keeping a tight hold on it as his face sombered. “Felix… are you sure about this?” 

“Yes.”

“But Fe… you’ll die if you do this.”

Felix was silent for a moment, not meeting his friend’s gaze. Then, words rushed together too quickly, he said, “If we don’t win this war, I’ll die anyways. We all will.” 

“Dimitri wouldn’t want you-”

“I don’t care what Dimitri wants,” Felix snapped. 

“Well, what about Ingrid? And me?” He swallowed, putting a tentative hand on Felix’s shoulder. “You don’t have to do this, Felix.”

This time, he didn’t shrug Sylvain off. 

“You didn’t even think this was real a few hours ago. You thought it was fake.”

Had he? 

Huh.

That surprised Byleth - Felix had taken all of this pretty well in stride for someone who hadn’t thought she was real. 

Sylvain tried again. “What about our promise? You remember? The one we made when we were little?” 

“Would _you_ do it?”

“Huh?”

Felix nodded in Byleth’s direction. “If it had been me she attacked and not you - if you’d brought the Lance of Ruin. Would you make the deal?”

“To protect Faerghus?” 

Sylvain considered this carefully, not answering for several minutes. “I guess… I guess I would,” he said finally. He ran a hand through his hair, exhaling a shaky breath as he shot Felix a sad smile. “If it meant we could win this and go back to the way things used to be? Well,” he broke off with a weak laugh, “Not _just_ like things were before. A few good things have happened.”

He held out the contract, and Felix reached for it. 

But Sylvain didn’t let go. “Felix - I…”

Felix yanked a little harder. “Don’t lecture me,” he said. “I’m doing this.”

As if to demonstrate this, he turned to Byleth, holding out a hand for the pencil. She dropped it into his hand, and he caught it, deft, before reaching for the contract once again. 

“Sylvain,” he said. 

“I just - I want there to be another way,” Sylvain said quickly. “This doesn’t seem fair.”

Felix snorted. “Life isn’t fucking fair, Sylvain,” he muttered. 

“You have me there.”

Sylvain finally relinquished his grip, taking a step back. “Okay,” he breathed. “Okay. Sign the damn thing.”

“I plan to.”

Felix laid the contract down on the altar, gripping the charcoal tight. Byleth watched as he leaned down, getting closer and closer to the document. A catch, she reminded herself, this was a _steal_ -

So she wasn’t sure why she did it.

She stepped forward, catching his arm just as he was about to sign. She wanted him to be sure; she wanted him to understand what he was getting himself into here. If he didn’t-

Felix jerked, staring up at her. “What?” he demanded.

His cheeks were still pink; they had been throughout the duration of his conversation with Sylvain. Would his skin be hot, she wondered? Would he turn even redder if she touched his face?

She let go, remembering herself. 

“Nothing,” she said. “Sorry.”

Felix darted away from her as soon as she freed him, signing away his soul with little flourish.

“There,” he said brusquely, shoving the pages of the contract across the altar towards her. “I signed it. What else?”

“Nothing. That’s it.” 

“That’s it?”

Byleth raised an eyebrow. “Were you expecting some kind of fanfare?”

“What? No.”

”Little imps popping out of the ground, throwing ashes in your face?”

”I said no, dammit-”

“That’s it, Felix.” She rucked the contract into one of the pockets of her coat for safekeeping. “Your soul is mine now.”

There would be proof too - physical evidence of their binding agreement. It would show up very soon, if her instincts were correct. Just a few minutes, surely- 

Felix groaned, clutching at his neck.

“Felix?” Sylvain stepped forward, worried. “What is it?”

“My neck - fucking _burns.”_ He glared at Byleth. “What did you do to me?”

“It’s a part of the process.” She reached for his hand, slowly prying it away from his neck. “A mark - to let the other demons know who you belong to.”

“ _Belong to-“_ he seethed. “I’m not a thing to own!”

“Mmm.” She tugged on the collar of his turtleneck, watching as her brand was slowly etched into his skin like a tattoo. “I have a signed contract that says otherwise.”

“Fucking _shit-”_

“What are you doing to him?” Sylvain demanded, one hand reached out to Byleth as if he could stop her.

“Nothing.”

“This isn’t nothing!”

She rolled her eyes, letting go of Felix. He staggered backward, his hand coming back to rest at his collarbone.

“Like I said - it’s a mark. My mark. He won’t be able to make another demonic deal while he wears it.” She watched as Felix straightened, the tension easing from his shoulders as his mark was completed. “It should be done now. It’s quick.”

Felix tugged at his collar. He tried in vain to look down at the mark, searching for it with his fingers when he realized he wouldn’t be able to see it. He traced it, thumb smoothing over the whorls and angles, committing it to memory. His breath hitched it he realized that it was the same as the mark adorning her neck.

“This is-” 

“Yes. The mark of the queen of hell.”

”It’s your sigil? As well as hers?” 

Byleth nodded, and Felix’s eyes narrowed.

”What does that mean?” he demanded. 

“Isn’t it obvious?” she asked, shooting him a pointed look.

”Enlighten me,” he snapped.

”Once upon a time, I too made a deal with a demon. _The_ demon.”

Across the way, Sylvain gasped. “Oh, fuck,” he whispered.

Oh fuck, indeed.

“She gave me what I wanted - and ten years later, she took my soul.”

”What did you ask for?” Felix asked.

”My father had just died,” Byleth replied. “And I didn’t have anyone else. I asked her what anyone would’ve asked for. But demons can’t bring the dead back to life - not even the queen of hell herself. She didn’t grant my first wish.” 

“And what was your second wish?”

Her eyes flashed. 

“If I couldn’t have my father, I thought I’d like to meet my mother.”

“Your mother.”

“My mother - the handmaiden of an archdevil named Rhea.”

Sylvain put the rest of the story together, working faster than Felix. “Then you... that means-”

Byleth nodded. “Yes,” she replied, turning back to Felix. “I asked her to make me a demon. She did. I bear her mark. And you,” she added, moving until she stood directly before Felix. “Now bear it as well.”

For once, he didn’t seem to have a comeback. He just stared at her, lips parted, but no words escaping, and she stared right back.

“Shall we go to your camp then?”

That snapped him out of it. “What?”

”If I’m to help you win this war, I need to see your army.” She paused, lifting an eyebrow. “You do have an army, right?”

”Of course we have an army,” he retorted.

”Purely out of curiosity... what would you have done if we didn’t have one?” Sylvain asked.

Byleth considered this as she started towards the path that led out of the forest. “More or less the same.”

“Oh, good,” Sylvain wheezed. “Did you hear that Felix? Her plan was the same _with or without_ an army. What the _fuck-”_

Byleth smiled to herself, only half listening as the two men got into it.

This... was going to be fun. 

**Notes for the Chapter:**

> Littttttttttttle bit of angst, but I promise this has a happy ending!
> 
> Thanks for reading, as always :)


	3. Chapter 3

Dimitri shook his head, lips pursed into a thin white line. “You shouldn’t have done it, Felix,” he said. “You shouldn’t have made the deal. I didn't want any of you to sacrifice yourselves like this."

Felix snorted. That was rich, coming from him.

“Then you shouldn’t have fucking rushed a demon and taken yourself out of commission before _you_ could make the deal,” he retorted. 

Beside him, Ingrid winced, hands fisted into the fabric of her pants. There was something eating at her; Felix could tell. She’d been like this since they had returned from the forest, barely able to look at him, her expression crestfallen. 

He’d about had enough of it. 

“Spit it out,” he said, sighing. 

She looked up at him, green eyes wide. “I-”

“If you have something to say, then say it. Otherwise, stop looking at me like that.”

“How could you do it?”

Her voice was quiet, surprisingly calm.

“How could you sell your soul to that… that demon?”

He huffed. “It wasn’t like I had a choice.” Dimitri opened his mouth to protest, and Felix glared at him. “I _didn’t,_ ” he snapped. “If I hadn’t taken the deal, the demon would’ve left and not come back. Don’t pretend you would’ve done differently.”

To his credit, Dimitri didn’t. 

Ingrid was a little more stubborn.

“There must have been another way,” she insisted, “something that won’t result in you _dead_ in ten years.”

Death.

He’d not thought about it much. At twenty-three, there hadn’t been much reason to be concerned with his own mortality. He was young, he was healthy - most importantly, he was strong. Even though they were at war, he had faith in his ability to keep himself alive. If he _was_ cut down, he imagined it would be just like that - a quick, sharp death on the battlefield, minimal pain before he succumbed. 

He wasn’t sure how it would go with the demon - Byleth, he reminded himself. She’d finally given them her name on the way back to camp. 

“So you can quit calling me ‘demon’,” she’d said, voice flat. 

“It’s what you are,” he’d pointed out.

“Fine, _boy_.” 

He’d bristled at that, but seen her point. 

How would it go, when she reaped his soul? Would it be painless, the same as falling asleep? Or painful as any wound he might sustain in the field? He tended to think it would be more like the former, but who the hell knew, really. This was uncharted territory here. 

“What are you going to tell your father?”

Immediately, Felix bristled. Across the way, Sylvain whistled, sliding a little lower in his chair, getting out of striking range. Even Dimitri blanched a little, eye roving wildly between the two of them.

“Nothing,” Felix snapped. 

“ _Nothing?”_

“Why should I?” he demanded. 

“You’re going to _die,_ Felix, because you made a deal with a _demon._ You don’t think he deserves to know that?”

“You tell him then,” he said. 

“What?”

It had mostly been a hot retort, something he’d said before really thinking about it. But now that he’d given voice to it, he liked how it sounded. He wouldn’t have to deal with Rodrigue, Ingrid could foist her worrying on someone else… it was a win-win situation, really. The two of them could go commiserate about it together, grieve for him before his body was even cold.

“Since you care so much, _you_ tell him,” he continued. 

“I… I couldn’t,” she said. 

“Why?”

“It’s - it’s not my place.”

Of course it wouldn’t be that easy. 

Felix knew he’d have to tell the old man _something._

Eventually. 

This wasn't the sort of thing that he could keep quiet forever. It wasn’t going to be an easy conversation. But then again, his conversations with Rodrigue never were. 

“Do you have a… a plan?” Dimitri asked, voice quiet. 

Felix had a will, if that was what he meant. They all did, being the respective heirs to their houses. With the war, it was a necessary thing. Any one of them could die in battle, at any time. 

As for him, he and his father had agreed that if he were to die, the title and dukedom would pass to his uncle, currently serving as warden of the Fraldarius manor and lands. With several children of his own, the family line would continue through him. 

“Yes,” he replied. “I have one.”

Sylvain sent him that _look_ , the one so sad and knowing it made Felix want to punch something.

“What?” he demanded, unable to stand it, but Sylvain merely shook his head. 

Ingrid started to rise up, mouth opening, but he put a hand on her arm, dragging her back down into her chair. “It’s done, Ingrid - you can’t change it.”

“Like hell I can’t,” she snapped, shrugging off his arm. She turned back to Felix, undaunted. “Can you talk to the demon? Find a way out of this?”

Dimitri shot her a wan smile. “Ingrid, I believe Sylvain is right-”

“Don’t say that! If she made this deal, she can _unmake_ it just as easily.”

Sylvain shook his head. “I read that contract, front to back,” he said. “It’s ironclad. Unbreakable.” 

“Even if I could break it, we’d lose her help,” Felix pointed out. 

“And possibly the war,” Dimitri added.

She didn't want to give up. Her mouth worked furiously for several moments as she tried - and failed - to form another rebuttal. “Then we’re just… we’re just _stuck_ with this?” she finally demanded.

"Yes."

"Seems like it."

“We are… stuck with it," Dimitri concluded. "And ten years from now, we shall face the consequences.”

Guilt. They were all riddled with it. Felix could read it in the stoop of their shoulders, their downcast gazes, how none of them could look at him without those stupid, fucking looks on their faces. Sadness, despair, _pity_ -

He hated it. 

He _hated_ it.

He was still alive, dammit, and with any luck, he would be for the next ten years. There was no sense in mourning someone who wasn’t dead yet. 

“What are we going to do with the demon?” he asked. 

It was an abrupt change of subject, and he knew it - but another minute of that pregnant, solemn silence and he’d have well and truly lost what little patience he had left. 

“We have her help," he continued, forcing the issue. "How should we use it?”

“Take her to Linhardt,” Sylvain suggested, after a moment. “See what he thinks.” 

Felix scoffed. “So he can poke and prod her like she’s some kind of experiment?” 

Sylvain shrugged. 

“He… is the expert,” Dimitri pointed out. “Perhaps Linhardt could test her abilities.”

Felix didn’t think there was a soldier among them that could put her to the test. So the idea of Linhardt, who he’d be willing to bet had never seen a day’s combat in his life, trying to gauge her prowess was laughable. They’d have better luck with that if he invited her out to the training grounds himself. 

Maybe that’s what he would do. They could spar. She'd win, most likely, but he'd get an idea of what her fighting style was, what techniques she liked to employ.

The three of them had continued on as he'd contemplated this idea. Ingrid was speaking now.

“At the very least, he might have an idea where she would be most effective in battle.”

“On the front lines, surely.”

“I’m not so sure,” Dimitri mused. “She’s powerful, yes, but if we put her out front, the enemy will throw everything they have at her to take her down. While I don’t doubt her abilities, against enough foes... Perhaps she would be better as the leader of a targeted attack group - a strike force. She could infiltrate the enemy camp, or help flank the opposing army.” 

Felix scowled. “What do you think Linhardt knows about any of this?” he demanded.

“He’s a renowned scholar, Felix, even outside demonology-”

“He got lost finding the _mess tent_ yesterday - because he confused the _farrier_ for the _quartermaster.”_

“To be fair, they’re both named Harold,” Ingrid pointed out.

Felix blinked.

“Yeah, Harold the Younger, and Harold the Older,” Sylvain piped up. “No relation, though. I asked once - the younger Harold. I think.” He frowned thoughtfully. “Actually, maybe it was the older…”

"They do look very similar," Dimitri admitted.

“This is all beside the point,” Felix snapped. “Linhardt’s never been in a battle. He can’t help us strategize for one.” He shifted from one foot to the other, arms crossed over his chest. “Why are we even taking his advice? We just met him two days ago.”

“And since then, he's provided valuable intelligence on Edelgard’s forces,” Dimitri replied. “Troop numbers, supply lines, merchant shipments… he’s the son of the minister of the interior, you know. He had access to quite a few privileged documents before he fled.”

“And he just - gave that information to you.”

“Yes.”

“Freely.”

Ingrid hesitated. “Should we be suspicious of him?”

“You should be suspicious of everybody,” Felix retorted.

“I’m aware that he could be a spy, Felix,” Dimitri said, a touch gently, as if he were placating a child. Felix’s hands fisted into his shirt sleeves. “Or at the very least, giving us unreliable information. But his numbers match what our own spies have concluded. And our agents in the Alliance confirmed the movements of their merchants - exactly the paths Linhardt had said they would take. His word has been good.”

“Besides, he has no reason to lie,” Sylvain pointed out. “He fled the country as a senior bureaucrat’s son - one central to their war effort. That’s got him branded a traitor; if he doesn’t want to lose his head, he needs to find someone to protect him.” He jerked his head sideways, towards Dimitri. “Just so happens, Dima’s the only Blaiddyd left. He’s the only one who can offer him immunity.”

Dimitri nodded. “Edelgard will no doubt demand we extradite him if she gets word he’s here. But so long as he aids us, I see no reason to acknowledge that request.” 

Felix snorted. “She’ll just send an assassin,” he pointed out. 

“An eventuality we’re prepared for,” Dimitri replied. “Linhardt too - he’s well aware of the situation. I’ve set several of Dedue’s men watching him.”

“Babysitters.”

“A necessary precaution.” 

“You don’t like Linhardt,” Sylvain said suddenly. 

Felix snorted. “I don’t _trust_ Linhardt.”

“You don’t like him either.”

“I don’t like anyone.”

“You like me,” Sylvain disagreed. 

“And me,” Ingrid pointed out.

Dimitri, tactfully, didn’t answer.

“So what’s wrong with Linhardt? Is it that he’s not a warrior?”

“Of course not,” Felix snapped. 

And it wasn’t - not everyone was cut out to be a warrior. That was fine. Armies needed healers, and blacksmiths, and cooks, and medics, and all other sorts of people, functioning together like a well-oiled machine. Not everyone needed to be a fighter. 

It was more that Linhardt had no drive. No ambition. No goals.

He said he was studying demonology, that it was his life’s work, but he hadn’t even bothered to come with them yesterday to the demonic altar. He’d been too busy _sleeping_. 

It was… lazy. Indolence. Sheer, unbridled sloth. 

There was very little Felix hated more. 

That he should be one of the few they deemed worthy enough of divulging Byleth’s true nature to - it irked him. Endlessly. Like a splinter under his skin, one that itched and burned the more he picked at it.

“Felix?”

“Fine. I’ll take her to Linhardt.” 

He spat out the words, angry, unable to properly articulate why he didn’t want to do so. Typical. 

“Are you sure?” Ingrid asked, “You seem-”

“Angry,” Sylvain interjected. “Definitely angry.”

“I’m not angry -”

A blatant lie.

“-I’m _annoyed_.”

“At us.”

“At-” All the breath left him at once, and his anger faded nearly as quickly as it had come. “Nothing.” 

Everything.

Dimitri nodded, clapping Felix on the shoulder. “Thank you, Felix,” he said. “When you’re finished, show her around the camp. And take her to the training grounds. I want to know what you think of her abilities.”

He thought her abilities were beyond anything any of them had ever seen - but if it gave him a chance to get away from everyone else for a while, to study her techniques more closely, he’d take it. 

He nodded, shrugging off Dimitri’s hand in the process. “Alright.”

Dimitri, unperturbed by the slight, moved past him to the tent’s entrance, his hand questing for the break in the fabric. At the last moment, he paused, turning back towards the rest of them.

“Oh, and Felix?”

Felix lifted an eyebrow.

“Don’t let anyone see you, should you spar with her. I think it’s best the extent of Byleth’s abilities stay as private as possible for now.” 

* * *

“I can’t believe it.”

The newcomer looked Byleth up and down, putting a hand to his chin as he walked around her in a circle, inspecting her from every angle. 

“I’d always thought there was some truth to the legends, but _this…_ ” He paused, coming to a halt just in front of her. “You, demon.” 

Byleth raised an eyebrow. 

“Do something.”

“...something.”

“Something demonic.”

She blinked.

Behind him, still sitting in the chair across from the newcomer’s desk, Felix snorted. 

“Can you do magic?” He frowned, reconsidering. “No, don’t answer that - of course you can use magic. Felix mentioned you summoned a contract out of thin air and somehow transferred your sigil to him. What is that, if not magic?”

He paused again, staring at her intently.

It was actually a bit unnerving. 

“How can I know your powers are true?” he mused. “How could I test you?” 

Felix was staring at her too - but not the way an interested party might study an insect, as the other man was. No. It was more than he wanted to see what she’d do next, mildly interested in whatever “demonic” thing she might come up with. 

It half made her want to impress him.

“Could you take me to hell and back?”

“What?” Byleth asked, startled into speaking. 

“Yes, that - that would work! I’ve always been curious about what hell might look like. And if you could take me, it’s clear proof that you are what you say you are.”

“That isn’t a good idea.” 

Blue eyes flashed. “Could you do it?”

Could she? Yes.

Would she? No. 

The denizens of hell would - literally - tear him to pieces for the fun of it unless she protected him.

Something she wasn’t terribly inclined to do, to be honest. He’d poked her in the forehead when they’d first met, to “check if she was corporeal”, and she’d not forgiven it. 

“Don’t be a fool, Linhardt,” Felix snapped, finally giving Byleth a name to put with the face. “She isn’t going to take you to hell.”

“Why not? It’s a perfectly reasonable request-”

“Reasonable,” Byleth said. “You think asking a demon to take you hell is _reasonable_ -”

“Can you think of another way to prove who, and what, you are?” Linhardt demanded. “Definitively?”

“Proof?”

“I accept Felix’s hypothesis - your sigil is unlike any crest I've ever seen, and the weapon you bear _is_ intriguing, but the possibility remains you may be nothing more than a talented charlatan, tricking people who venture too far into the woods-”

Perhaps her earlier judgment had been too hasty. She might _like_ taking this one to hell. 

Maybe she’d push him into the lake of fire, while they were there. Feed him to the wyrm that liked to bathe in the flames. 

“A charlatan,” Byleth repeated. 

“A very _skilled_ con, but a con nonetheless-”

“I _am_ a demon-”

“So you say.”

“-and I have been for centuries.” 

“Again - so you say.”

Felix huffed, expression halfway between annoyed and bored as he turned back to Byleth. “Do something,” he snapped. “Else he’ll never shut up.”

“Something.”

He threw up his hands, as at a loss as she was. 

She thought about it, considering her options. There were several things she could do that would prove she was a demon - but most of them were messy, or required her to physically maim the long-faced skeptic. And while he was being annoying, she wasn’t _that_ far gone just yet. 

She needed something else, something both simple and impressive. She needed-

Time.

Of course. 

“Tell me something only you could know,” she said.

Linhardt raised an eyebrow. “I beg your pardon?”

“Tell me something,” she said again. “A secret. Something you’ve never told anyone.”

“Why?”

“You’ll see.”

He studied her for a moment, trying her suss her out; eventually, he sighed and relented. “Fine,” he said. “Let’s see… I once fell asleep in the middle of a practice battle while I was at the academy, and no one bothered to wake me up. They just put me on a horse and sent me back to my house's camp.”

Byleth frowned. “I find it hard to believe no one saw that,” she said.

“Then why didn’t they wake me up?” 

“Probably because you were more useful back at camp,” Felix muttered.

Linhardt made a thoughtful face, followed by a noise of agreement. “I suppose that’s true, actually.” 

“That’s not good enough. I need something deeper,” Byleth insisted. “Something you’d be shocked if anyone else knew.”

Linhardt grumbled. “More embarrassing than that?”

She shook her head; he was getting lost in the details. “It doesn’t have to be something embarrassing. Just so long as it’s personal, it will work.”

“This all seems rather invasive.”

“Yes. That’s the point.”

He sighed. “But I suppose if it’s in the name of science…” He paused, clearing his throat. “I told the prince and his friends that I left the Empire because I feared her Majesty would declare me a heretic based on my interests and pursuit of demonology. This is true. But before I left, my father threatened to disown me, calling me a slovenly waste of space who’d sooner spend time with his books than his peers. So, really, I had no other options.” He crossed his arms over his chest, shifting from one foot to the next. “Was that personal enough, demon?”

“Yes.” 

“I still fail to see why you needed to know that.”

“Give me a moment.”

Byleth closed her eyes, sliding down deep into that well of power that lay dormant inside her. Another gift from Sothis, this wasn’t just any ordinary talent; the queen had gifted her with the ability to turn back time itself. She didn’t use it very often. It was more taxing than she’d like to admit, and going back in time didn’t necessarily mean the outcome of events was any different. 

Sometimes you stepped on a butterfly and entire dynasties collapsed; other times you’d slaughter a whole battalion to save a man and he’d still die at the dinner table. 

Time was funny that way. 

But the ability to move backwards along the timeline would serve her purpose now, and so she grabbed that little seed of power inside herself, nudged it, grabbed the flow of time and _yanked-_

When she opened her eyes again, Linhardt was still standing before her, and Felix was still sitting in a chair across the room. But where Linhardt was, again, asking why it was such a bad idea for Byleth to take him to hell, Felix was staring at her sharply, confusion writ large on his face. That was odd; things should have been precisely as they'd been several minutes ago. But she didn't waste time pondering it, turning back to Linhardt.

“Your father threatened to disown you,” she said, cutting him off mid-sentence.

Linhardt turned back towards her, eyebrows lifted. 

“He kicked you out, called you lazy,” she continued. “You told people that you left the Empire so you wouldn’t be branded a heretic. But that wasn’t the only reason.”

He didn’t deny it, instead blinking at her rather owlishly. “And how do you know that?” 

“Because you told me.”

“I don’t recall-”

“You told me five minutes from now, when I asked you to tell me something only you would know.”

Linhardt’s brow creased in thought. 

“Your father's exact words were ‘a slovenly waste of space who’d sooner spend time with his books than his peers.’”

“That does sound like something my father would say,” he mused. “But why would I tell _you?_ ”

“Because I asked you to - to prove to you that I am what I say I am.”

It took him a moment to process all of this - but, to his credit, there wasn’t an ounce of disbelief on his face. It seemed more like he was fitting pieces together, trying to come up with a whole. 

It seemed like a success, if the awed look on his face was any indication.

“Fascinating,” he said. “You can alter the flow of time? I’ve never heard of such a power before! Does it work both ways - or can you only travel in one direction? Could you do it again - on someone else perhaps, so I could see its effects?” 

Felix stood, the legs of his chair scraping noisily against the floor. “Not now,” he said.

Linhardt ignored him, already grabbing for a notebook and a quill. “I’ve got to write this down,” he muttered. 

“You,” Felix said, pointing at Byleth. “Outside.”

Without another word, he stomped out of the tent and into the pouring rain. 

Byleth shrugged, following. “I’ll come back later,” she threw back over her shoulder. 

And she would - if she was feeling generous. And she had nothing better to do. 

Regardless, her quick departure didn’t seem to faze Linhardt - he’d started scribbling away on a blank page, nose almost pressed against the paper, he was leaning so close, and he merely waved her off as he kept writing. 

A true scholar. 

Felix was waiting for her under a nearby tree, pacing a line into the mud. He looked up as she approached, expression guarded. 

“What the hell was that?” he demanded.

“What was what?”

“That - that thing you did in there,” he spat. “You never said anything about going back in time.”

“Should I have?”

The glare he leveled at her told her he thought as much. 

“When you - when you did _that_ , I felt it,” he explained. 

Ah. 

_That_ had never happened before. She supposed that explained why he'd looked so startled after she'd moved time. 

“What do you mean, you felt it?” she asked.

“There was this - I don’t know, this _pressure_ , and then everything was moving backwards.” He huffed. “I didn’t know what had happened until Linhardt asked that stupid question about going to hell again, exactly as he had before.” 

“But you remember the conversation that happened before?” she prodded. 

“About getting Linhardt to tell you something personal?” She nodded. “I remember it.”

“Interesting,” she murmured. She eyed him, wondering if there was some magic in him that she’d not noticed before, something that would prevent her time-manipulation from working. But no, there was nothing, nothing save for the usual offensive spells some humans could cast. That meant-

“It must be the mark.”

“What?”

“When I marked you,” she said, gesturing to his neck, “It must have given you a shred of my capabilities. That’s the only way you could see what I was doing.” 

He crossed his arms over his chest, frowning. 

“I’m not affected by the magic,” she continued. “No matter how far back in time I go, I remember what happened before. But for everyone else, that isn’t the case. If you can remember my conversation with Linhardt-”

“Then it didn’t affect me either,” he finished.

“Exactly.”

He nodded, satisfied at that. His immediate concerns resolved, his expression turned speculative. “This magic. Can all demons do this?” 

“Just me,” she said. 

He stared at her. 

“Well. Me and the queen of hell,” she added. He snorted. “But we’re the only ones.”

“It seems useful.”

She grimaced. “Not as much as you’d think,” she replied. 

He lifted an eyebrow at that, clearly not believing her, and she launched into a deeper explanation. She hated how much it sounded like a lecture Seteth had once given her.

“People think time is like a line, but it isn’t. It’s hundreds of thousands of lines, all of them branching off in their own directions - a hundred billion possibilities, based on every single choice people have to make, every little thing people do. Going back in time isn’t just me changing one thing, even if that’s all I do - it’s me changing an infinite number of things, forever, my action ricocheting through events.”

“A ripple effect.”

She nodded, glad to see he was grasping the concept. “Sometimes, those ripples matter; sometimes, they don’t. But trying to plan for everything, trying to figure out what matters and what won’t - it’s a pain in the ass, honestly.” 

“Then you don’t use it?”

“Not unless I have to,” she said. 

Or, as with Linhardt, where the effects would be small and very little was at stake. 

“And how many times have you had to use it?”

“Twice. Not counting today.”

He looked curious, like he wanted to ask what those two times had been - but he didn’t, clamping down on the question before it could leave his mouth. 

“You should’ve mentioned it,” he said instead.

Her lips twitched at his petulant expression. “Okay.”

He huffed, stomping the toe of his boot into the ground. “Are there any other surprises I should know about?” he demanded. “Other… abilities of yours?”

Byleth blinked. “I'm a mean hand at cards, if you know what I mean.”

“That’s not-”

“And I’m pretty good at fishing.”

He glared at her. “That isn’t what I meant, and you know it.” 

She raised an eyebrow. “Do I?”

“Do you have any other - _magical_ abilities,” he ground out.

“Oh, loads.”

He rolled his eyes, a hot retort on his lips.

“But nothing I can use to help you win this war,” she finished, before he could speak. 

It was against the rules. He’d made his wish. He couldn’t have another. 

Now if someone _else_ wanted to sell her their soul for the good of Faerghus - maybe the redhead with the big mouth - now _that_ was a deal she’d gladly make. 

Felix was staring at her suspiciously, like he didn’t believe her. 

Byleth couldn’t blame him. She wasn’t sure she’d believe her either. 

“You’re sure?” he asked.

“Positive.”

“Then the time magic is-”

“Special,” she said. “And I won’t be using it to help you either.”

“Good.”

“Good?”

“Good,” he said more firmly. "I don't like it."

She didn't either, to be honest. But Sothis wouldn't take the power back. She'd asked once. 

The queen of hell had hit her on the head with her scepter, called her an ungrateful child, and gone off the pleasure gardens for some tea. So that had been the end of that particular conversation.

Now that they’d gotten that out of the way, he cleared his throat and jerked his head the opposite direction. “Let’s go to the training grounds. I want to see what you can do.” 

She'd been wondering how long it would take him to ask her show off her abilities. When they'd first arrived back at camp, yesterday night, she'd thought he'd drag her off then and there. He'd seemed very intent upon it, back in the woods. Instead, he'd deposited her at an empty tent, gruffly told her to mind her own business, and stomped off. 

“Without magic?” she clarified.

“With your sword.” 

“Ah.”

“It’ll be just us - Dimitri doesn’t want anyone else knowing about you yet.”

A wise move - most humans didn’t take too kindly to the knowledge there was a demon amongst them. Again, Rhea’s doing. 

She ruined _everything,_ damn her. 

“Will you fight me then?” she asked, falling into step beside him as they stepped back out into the rain. 

Messy weather for a spar, she thought. Rain in her eyes, mud on her boots, hair plastered to cold, wet skin… A good way to test someone’s adaptability - how they’d correct their form if they slipped, how they accounted for a shallower field of vision. 

She’d like to see how Felix fought in the rain. 

He eyed her speculatively, turning his eyes back to the path ahead of them before he answered.

“Maybe,” he said. “So long as you don’t throw me into a wall.”

Byleth shrugged, following after him. “No promises.” 

**Notes for the Chapter:**

> Linhardt: *pokes Byleth*
> 
> Byleth: *blinks demonically*
> 
> Linhardt, Barbara Walters voice: "Fascinating."
> 
> Thanks for reading! :)


	4. Chapter 4

**Notes for the Chapter:**

> I'm only *mostly* dead I promise. So sorry for the delay, health issues have kept me from doing much of anything lately

Byleth hefted the training sword in her hand, getting a feel for its weight and balance.

The wooden hilt was smoother than the rough bone of her own weapon, worn down from the hundreds of soldiers that had borne it before her. She would have to adjust her grip to keep ahold of it - and adjust it again, to keep the rain from allowing it to slide out of her fingers. The blade, too, was different. Only half as wide as the Sword of the Creator, and perhaps two-thirds as long, she wouldn’t have nearly the same reach. She would have to get closer to her opponent to strike, moving herself into range of their own blade.

But she’d been taught how to attack from all angles, with all sorts of weapons. Her mercenary father would have accepted nothing less. Working with a practice sword was like meeting an old friend, familiar and comfortable.

Across from her, arms crossed over his chest, Felix was watching her every move. She wasn’t sure what he expected to see - after brusquely handing her the sword and stepping back, he hadn’t bothered to tell her what he wanted her to do. So she’d gone through with a few swings to warm her muscles up; she let herself get a feel for the blade and tested the ground with her feet to see just how soft the mud beneath her feet really was.

It was the sort of thing any experienced soldier would do when handed a new weapon. Very normal. Very boring. Hardly something to show off the extent of her skills. 

She’d need to move around a little more for that.

Having tested the blade as much as she liked, she relaxed her grip and let it fall down to her side. Then she turned to Felix, pushing her wet bangs out of her face.

“Fight me.”

He didn’t reply - but she saw his hand twitch towards the sword strapped at his hip. Habit, probably. An instinctual response to a challenge.

“You know you want to.”

He snorted. “I’d also like to keep my insides where they belong,” he retorted. 

Byleth raised an eyebrow, looking down at the blade in her hand. “Evisceration would take a lot of effort with a wooden sword,” she said.

A lot more effort than she was willing to put into this, to be honest. 

It was a _very_ old sword. 

Probably would’ve worked better as kindling than a weapon.

“I’ll go easy on you,” she offered, trying to sweeten the pot.

That earned her a glare, Felix turning on his heel and stalking over to the rack of weapons at the other side of the grounds. With practiced eyes, he picked a suitable sword out of the group and walked back towards her, whipping the blade out so that it was pointed towards her neck.

“You’ll do no such thing,” he snapped. 

Byleth shrugged to cover a grin, secretly pleased that all it had taken to get him moving was a little goading on her part.

Touchy, this one. Very touchy.

No sooner had her shoulders settled back into place than Felix was rushing her, blade slashing out at her face. With a twist of her wrist, her own weapon snapped up, easily batting aside Felix’s strike - but already he was ducking back, moving out of her range. 

A test. 

He’d wanted to gauge her reflexes, see how quickly she responded. Her lips quirked up in amusement when he repeated the movement, coming in from a different angle this time. 

Again, she swatted it aside, moving with Felix as he circled away. 

“You can do better than that,” she said. 

He snorted, but didn’t disagree. 

Eyes never leaving his, she darted forward, blade striking up and out faster than the eye could see. The wood hit, and she felt the familiar tingle of impact run up her arm, sending a fresh burst of excitement through her veins. 

Felix staggered back, one hand coming up to his chin; though she hadn’t broken the skin, it was already starting to bruise, a dark ugly blossom on his jaw. 

“Too slow.”

The look he shot her was pure venom, and he slipped back into a fighting stance. “Shut up.”

This time when she struck, he was ready - he caught the edge of her blade, just barely, parrying it away. It was a wild move, swinging him off balance, and Byleth slipped back in to swipe her sword at the back of his thighs. He fell, one knee squelching deep into the muck, a hissed breath the only indication the hit had been painful. Then he was back up, lunging towards her in a counterattack, and Byleth was put on the defensive. 

She let him drive her back, ceding some ground as she blocked his strikes. He was so fluid, moving effortlessly from attack to attack. Each swing of his sword was strong and clean - efficient, with none of the showy flicks and waves she’d come to associate with human fencing. Each attack was brutal, sharp, precise; he trusted that she was skilled enough to block his attacks, and so he wasn’t holding back.

She liked that.

Unfortunately, it wasn’t enough. 

Felix was skilled - that much was obvious. He could probably best more than a few demons in a one-on-one fight, with the right motivation. But he was still human. 

And she wasn’t just any demon.

The time for defense was over. Abruptly, she twisted, dancing out of his reach. Caught mid-swing, Felix had no choice but to follow through. Byleth twirled around him, the tip of her sword swinging about to smack into the sharp bone of his wrist, and the blade fell from his hands. 

He turned, one hand already balled up into a fist meant to drive the wind from her lungs-

But Byleth was already there, pressing the tip of the sword into his neck, hard, and Felix froze.

“Dead,” she murmured. 

He glared at her for a moment, breathing hard. But then he nodded, stepped back, and bent down to retrieve his sword, flinging the mud from the blade in one deft movement. 

“Again,” he said, slipping back into a defensive stance. 

She lifted an eyebrow, surprised. “You’re sure?”

His eyes flashed. “ _Again.”_

This time, Byleth was the aggressor. From the start, she had him on the run, working furiously to avoid her blade. He would dodge left, and then right, trying to get around her for a swipe at her flank. He never succeeded; though he was quick, his tells were too obvious. He would hold his breath just before he lunged forward, a little stuttered gasp as loud as a shout. And each time he met her sword with his own in a direct confrontation, he’d draw his lip between his teeth, threatening to draw blood.

They were little things - he probably wasn’t even aware he was doing them. A novice swordsman would be too busy focusing on the blade in his hand to bother looking at his face or listening to his breathing. But a more experienced opponent would learn what each meant very quickly. 

Still, his speed would make up for it in most fights. Even if one of his foes learned to read him in the heat of battle, Felix was likely the deadlier of the two. He was the perfect build for a swordsman - neither too tall nor too short, he presented less of a target than bulkier, harder-hitting soldiers. But his lithe, wiry build still packed plenty of power; fighting against him now, she could understand why he was one of the prince’s most able commanders.

Suddenly, he moved, bending over backwards in a move that had Byleth’s spine twinging in sympathy. Her sword sliced through nothing but air, her body following the path of the blade, its momentum unchecked. Then Felix was there, sliding down onto one knee, sword swinging up, blade moving straight towards her stomach in a move that would’ve gutted her had they been working with steel. 

She moved, impossibly fast, twisting back towards him, her sword swinging back round to meet his-

The wooden blades clacked together, no more than an inch from the bare skin of her torso. 

He smirked up at her, breath coming in great, heaving pants. “Almost dead.” 

Again, her lips twitched in amusement.

Brat.

She batted his sword away, reaching out a hand to help him back to his feet. He took it, wary, releasing her grip as soon as he’d risen. 

“You’re decent,” she announced. “But you need to work on your breathing. You telegraph your movements.”

He scowled, but nodded - a critique he’d heard before, perhaps?

“And you bite your lip too much,” she continued. “Anyone paying attention could read you in a second. Try to keep your face as neutral as possible; don’t move it at all if you can help it.”

“Like you?”

She blinked.

“It’s like fighting a corpse,” he said, “you staring at me like that.”

“I wasn’t staring.”

He snorted. “Yes, you were.”

“I was watching you - as I would watch any opponent.” She paused, tilting her head to the side. “Were you not watching me?”

He huffed out a breath. “Of course I was,” he said. “But I wasn’t staring. Not like you were.”

“Fine. You weren’t staring.”

“I wasn’t.”

She had to suppress a laugh as she turned away, making for the weapons rack to put the training sword away. Felix fell into step beside her, their boots squelching in the mud as the rain started to pick up again.

“So then,” she said. “What’s the verdict?”

“The verdict?”

“Am I good enough?”

He snorted, placing his blade beside hers in the rack. “You don’t need me to tell you how good you are,” he retorted. “You already know.”

She did. But it was nice to hear him begrudgingly admit it. 

“And your prince?” she continued. “What will he think?” 

The sound of someone clearing their throat cut through the rain, and the both of them looked up. A man was standing across the field - a very _large_ man, Byleth noted, dressed from head to toe in heavy plate despite the weather. Beside him stood Dimitri, eyeing the two of them tentatively.

Immediately, Felix scowled. 

“Why don’t you ask him yourself?” he asked, stomping away. 

She supposed she might as well - the newcomers were coming her way. A part of her wanted to trail after Felix; he’d offered to show her around the rest of the camp, after all. But the prince’s return had put him in a foul mood, and she wasn’t about to step in the middle of whatever bad blood was there. 

She’d find him again later.

“Lady Byleth,” Dimitri greeted her, offering her a small nod of his head. 

Byleth choked. “Lady?” she spit out, raising her eyebrows. 

Dimitri faltered, smile slipping. “It seemed… rude to call you otherwise,” he said. 

“I’m no lady.”

“Ah, as you say,” he acquiesced, again dipping his head. The man beside him shifted, and Dimitri started, gesturing towards him. “Forgive me! I neglected to introduce you to Dedue.”

“Your bodyguard?” she guessed.

“Dedue is a friend. And one of my most trusted advisors.”

Dedue offered Byleth a slight bow, his face betraying nothing of how he truly felt to be introduced to a demon. 

“How was your sparring with Felix?”

Byleth glanced over in the direction Felix had taken, unsurprised to find he’d vanished from sight. “He’s very good,” she said, turning back to Dimitri. “In a few centuries, he might have me beat.”

Dimitri chuckled. “He is very good,” he said. He gestured for Byleth to walk with him, and they set off towards the edges of the camp, Dedue several paces ahead. “That’s why I gave him control of the vanguard. Sylvain leads the cavalry, and Felix sweeps in behind on foot. Together, they’re quite effective.”

“But not effective enough,” she guessed.

“No,” he replied. “Not quite.” He turned to her, lips curving up. “You probably assume that’s where I’ll ask you to stand, yes?”

Byleth shrugged. “I’ll go where you need me.”

“That’s good to hear.” 

They drew to a stop on the edge of the nearby forest, well out of range of any prying eyes. 

“Some of my lords will no doubt want to send you to the frontlines, when they learn how strong of a warrior you are,” he continued. “I’m tempted to do so as well. However…” Here he paused, one hand coming up to cradle his chin. “There is something I wish you to see.” 

He turned to Dedue, who’d been thoroughly canvassing the area to make sure they were well and truly alone. Dedue nodded. “No one else is here,” he said, his voice sure but soft.

Dimitri pulled something out of the pocket of his cloak. “Take a look at this,” he said. 

Byleth stretched out her hand, and Dimitri offered her what looked like a small, round stone. “What is this?” she asked, frowning.

It was nondescript - abnormally smooth for a rock, and almost perfectly spherical, but much like any other stone she’d ever seen. The color was odd, though: a deep, dark red, almost the color of blood. And there was a strange mark on the far side-

Ah.

But of course.

She ran her fingers over the mark again, trying to memorize the pattern in her mind’s eye, before handing it back to Dimitri. 

“Do you know what it is?” she asked.

His eye flashed.

“Do you?”

Crossing her arms over her chest, Byleth replied, “It’s a crest stone.”

“We thought as much, too,” Dimitri said. “But it’s like no crest we’ve ever seen.”

“That’s because it’s a demonic crest.”

“You know it?” Dimitri’s voice was eager, the wariness in his gaze turning into something less guarded, more hopeful.

“I’ve… seen it before. But only in passing,” she admitted. 

There was… a face, in her memories. One she _thought_ was the owner of that particular brand. Sharp, cruel, pinched - the rest of the details were hazy, though. 

Including the demon’s name.

“Could you tell us which demon it belongs to?”

“Maybe.”

She’d have to call in a few favors, ask around. Preferably without said mean, pinchy face discovering she was asking.

It was considered rude to question another demon’s work, you see. What they did with their time was their business - and Sothis’, of course. Some of them were inclined to react... less than nicely, say, if they found out other demons were snooping about. 

“Where did you get this?”

Dimitri turned to Dedue, letting him take over the explanation.

“We took it from the carcass of a creature the Empire’s started using in battles,” he said. “They’re buried in the beasts’ foreheads, and they burn red like fire while the things are alive.”

“They give the creatures some kind of… power,” Dimitri mused. “They’re very difficult to kill, and can quickly overwhelm an unprepared group of soldiers.”

“An effective way of crippling our units,” Dedue said, nodding.

Infusing a beast with a crest wasn’t difficult - Byleth suspected some of the human mages could do it if they tried. The ones with greater crests, at least. It would take a lot of effort on their part, sure, and the spell would be dangerous to cast. But it was, theoretically, possible. 

That wouldn’t explain the demonic crest on the creature’s brow, though. Only a demon could bestow their mark upon another living thing. 

“When did you see the first crest beast?” she asked.

Dedue and Dimitri considered. “A year ago, perhaps?”

Dedue shook his head. “Not even. Gilbert was wounded fighting the first-”

“Ah, yes,” Dimitri said, nodding. “And that was-”

“Eight months past. Nearly to the day.”

She nodded, adding several more questions to the list of things she’d have to uncover on her next trip down south.

More down than south. Metaphorically speaking, of course.

Hell was more… alongside the human realm than above or beneath it. But all that was rather complicated, and she’d always dozed off during Seteth’s lectures on the various planes of existence. She preferred not to contemplate it too much.

“And the beast? What form did it take?”

“Reptilian,” Dedue replied. “Like a lizard.”

“Does that… help?” Dimitri asked.

“More than you’d think,” Byleth said. “I’ll have to go to hell to get any answers, though.”

“Anything you can uncover would be most helpful,” he said quickly. “We’ve been… struggling to find ways to deal with the things. I can send my strongest soldiers, those of us with more powerful weapons, out to disable the beasts. But that leaves them more vulnerable to attacks from the Empire’s main army. Which,” he admitted, a humorless laugh leaving his lips, “I suppose is the entire point. And why my lords will urge me to send you to the front lines.”

“I could destroy them,” she offered. “Take the heat off your men.”

“Of that, I have no doubt,” he replied. “But I’m inclined to send you somewhere else, if you could manage it.”

“...somewhere else.”

“The source.”

Ah. 

Several things clicked into place at once in Byleth’s mind, and she nodded, understanding.

“I have two problems, Byleth,” Dimitri said. “First, I must find a way to destroy these beasts without needlessly endangering my army. But second, and more importantly, I must find where they come from and stop them from being used against us at all.”

“If that’s even possible,” Dedue acknowledged.

“It must be - it _must,_ ” Dimitri pressed, turning towards the other man. “Think, my friend. We did not face these creatures in battle until this year. They are some new devilry of Edelgard’s.” He paused, turning to shoot Byleth an apologetic look. “No offense meant.”

She blinked. “None taken.”

“The Empire did something to send these things against us,” he continued. “Uncovered a summoning spell, or came across the magic in an ancient text somewhere. Edelgard took control of the monastery last year - perhaps she found her secrets there, uncovered in some hidden vault.”

“But we’d already searched Garreg Mach,” Dedue protested, shaking his head. “We held it for longer than she has, and searched all the tombs. What would they have found that we didn’t?”

Dimitri hesitated, and Byleth saw her chance.

“I don’t think she found anything,” she interjected. “Not like what you’re thinking, anyways.”

A few trinkets, perhaps. Mystical objects Rhea had “imbued” with holy magic.

And Linhardt had called _her_ a charlatan.

“Then why is this happening?” Dimitri demanded. “Why now, five years into this war? Why wait to press the advantage?” He huffed, stomping a foot into the ground. “Why _now_?” 

“And how?” Dedue asked.

“Isn’t it obvious?”

Neither had an answer for her, staring back at her blankly, and Byleth sighed.

Humans.

Couldn’t see the fish for the water.

“Felix isn’t the only one in Fodlan who’s made a deal with a demon.”

* * *

Later that night, as Byleth was sleeping, something awoke her. A little pop, a slight bit of pressure against her eardrums - a slight sound that most wouldn’t even have registered.

It was followed by a voice she’d recognize anywhere.

“Byleth.”

She groaned, sitting up on the tiny cot they’d given her along with her tiny tent, and flinging a bit of flame towards the oil lantern hanging in the corner. She _knew_ that voice.

“What _have_ you done.”

She opened her eyes, not at all surprised to see the green-haired man standing across from her, arms crossed his chest. 

“Something stupid?” she guessed.

“ _Incredibly_ stupid.” With a huff - and a surprising amount of grace - Seteth settled himself onto the stool at the foot of her bed, turning towards her with a stern look on his face. “We aren’t supposed to get involved in this war, Byleth. Sothis warned us against picking sides; you know this.”

“She didn’t _warn_ us-”

“It was just shy of a direct order!”

“Which means there was some room to maneuver,” Byleth shot back. “Besides, you know how she is. They’re more _guidelines_ than actual rules-”

“Byleth. She knows you’re here.”

Well, shit.

“How bad is it?”

“I believe the word ‘miscreant’ was thrown around.”

“Ah.”

“Flayn was worried you might come back before her anger has faded,” he continued. “She’s been waiting at the hell gate, intent upon catching you before you set foot in the palace.”

Byleth winced, fully aware of how dedicated Flayn would be to such a task. “I’m sorry, Seteth.”

He sniffed. “She sat there for three days, ignoring the rest of her duties. No one could convince her to leave her post. I finally told her that I would go and find you myself, to warn you away from returning to hell for the time being. It was the only thing that would give her any peace of mind.”

“Did she leave?”

“You know very well she’ll still be waiting for me when I return,” he snapped.

She did know that.

“Which is why you’ll be writing her a very _sincere_ letter of apology that I will take back with me.”

She nodded, reaching for the stack of supplies the army had seen fit to give her. 

“Five paragraphs. At least.”

Byleth wrote six, making sure to put as much remorse into the words as she could. Flayn was a sweet girl, and utterly devoted to those she called her friends. That she’d sat at the hell gates - where the lowest, most base demons lived, the ones that leered and jeered at anything that moved - so that she might warn Byleth of the queen’s anger, sat there for _three days..._

She signed the letter with little flourish, handing it to Seteth before the ink had even dried. “I’ll make it up to her,” she said. 

The noise Seteth made in response to that could only be described as a harrumph. “Please see that you do.” The ink having set, he folded the letter in half and tucked it inside his shirt. “Now, Byleth - to business. You have angered Sothis by agreeing to help Faerghus win this war. The way I see it, you have two options. You may cancel this particular deal and return to making petty agreements with the regular folk. Or you may alter the terms of your contract and help the army in a less obvious manner.”

Byleth didn’t think Felix was going to go for that. They didn’t need her help gathering supplies and training recruits. They needed her in the field. He’d been very clear on that point.

That left her with Seteth’s first option - canceling the deal outright. It was possible, though rare; all of their contracts had an annulment clause written into the language. She would still reap his soul, her mark on him permanent - but it would be at the end of his natural life. Not in ten years’ time. She would watch him from afar, and when the time was right, she would return to his side - to collect the debt.

In the end, the result was the same. She’d still collect the soul of a man with a major crest, offering it up to Sothis. But she’d have to _wait_ for it. Years, probably.

She never had liked delayed gratification. 

But how else could she convince Sothis to let her keep on with her current path? What could she do - or say - that would convince her queen that her actions were justified?

She needed something of equal importance - a distraction and an excuse, all in one. 

Her earlier conversation with Dimitri came to mind.

“Tell me,” she said, tilting her head to the side. “What does Sothis think of the other demon involved in this war?”

Seteth frowned, mouth falling open - but no words came forth.

“Why’s she spoken out against me, but not them?” Byleth wondered. “Is it because I’m so close to her? Because of all she’s given me?”

“What are you talking about?”

Byleth blinked. “The other demon,” she replied. “Why hasn’t she said anything about them?”

“ _What_ demon?”

“Whoever is creating the crest beasts for Adrestia.”

Seteth paused. “That is a grave accusation, Byleth.”

“I know.”

“Have you any proof?”

She gave him the crest stone Dimitri had shown her - he’d given it back to her after their conversation, urging her that it was probably safer in her keeping. Rubbish. Once the beast it had been attached to was dead, a crest stone was nothing more than a fancy rock. But she’d taken it anyways, hoping that looking at the sigil some more might jog her memory.

So far, no such luck. But now she had the evidence Seteth had desired, so maybe it was good that she'd taken it after all.

He turned the stone over in his fingers. “I haven’t seen this crest in years,” he murmured. “I thought…”

She waited for him to finish the thought, trying not to let her impatience show.

“I thought its owner dead.”

“You recognize it?”

“I must consult my records. But… yes. I think I do.” He looked up at Byleth, hand curling into a fist around the rock. “May I take this back with me?”

She nodded. “I was going to make the trip to you myself and ask you about it.”

“I wouldn’t advise going anywhere near hell,” he said quickly, wincing. “Not for a while, at least.”

“Sothis?”

“She was… quite furious, Byleth.”

Rats. Sothis’ wrath wasn’t something she’d factored into her plans.

“But I will search the archives, and if I find my suspicions are correct, I will inform you thusly.” He looked up at her, brow furrowed. “How did you come by this?”

She gave him a condensed version of what Dimitri and Dedue had told her, sparing only the trivial details. Despite the consternation in his face, he was clearly interested in the matter - the soft little noises he’d make as she gave her explanation told her as much.

“Curious,” he said once she’d finished, looking down at the crest stone again. “Very curious.”

“Seteth.”

“Yes?”

“Something else is bothering me. Who told Sothis I’d made a deal?”

He blinked. “I…” Then he frowned. “Come to think of it, I don’t know how she found out.”

“She knew about the deal I’d made within days of making it,” Byleth continued. “But whoever did this,” she said, tapping the rock, “did it without her knowing. They’ve been doing it for almost a year now. They’re _still_ at it. But Sothis still doesn’t know _._ ” 

The implications of that were staggering.

Not only was someone hiding within plain sight in the Queen of Hell’s court, but they’d managed to avert her gaze away from the human world enough for her to miss such a development. 

Abruptly, Seteth stood. “I think it best I not linger,” he said, tucking the stone into a pocket. “You’ve given me much to consider.” 

Byleth raised her eyebrows. “You’re leaving?”

“I don’t like this, Byleth. I don’t like at all.”

“But you haven’t even given me a lecture.”

Seteth snorted. “Did you want one?”

“I treasure every lecture you give me, Seteth.”

He shook his head in fond exasperation. “What do these humans think of your jokes, I wonder?” he mused, moving a few steps away. 

“Mostly they think I’m telling the truth,” she replied. 

“A frightening thought.”

“You’ll tell me what you find?” 

He nodded. “I’ll send word once I have answers.” 

Satisfied, she laid down again, easing the blankets back over her body. She’d just about rolled over, when Seteth’s voice caught her attention.

“Byleth.”

She paused, tilting her head to the side in question.

“Be careful. This isn’t an ordinary contract anymore - if it ever was.”

“I will.”

“Byleth.”

“What?”

“I am being serious.”

“So was I.”

“Don’t-” He sighed. “Who am I kidding? You’re more capable than most. Still.”

She allowed herself a smile. “You worry.”

“I _fret._ ” He sniffed. “Not overly much, I assure you.”

Uh huh.

“I’ll watch my back,” she promised. 

“Good.”

“And Seteth?”

Already, his form was beginning to flicker as he prepared to transition between realms. “Yes?”

“You watch _yours._ And Flayn’s.”

His green eyes flashed, steely and hard.

“Duly noted, Byleth.”

**Notes for the Chapter:**

> The plot thickens :o
> 
> Thanks, as always, for reading! :)


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